1

Interface MD

Validation

July 15, 2017

Hendrik HeinzDepartment of Chemical and Biological

EngineeringMaterials Science and Engineering Program

University of Colorado-Boulder, CO, USA

2

Validation Overview

• Lattice parameters are usually

3

Clay-Water Interfaces – Example Pyrophyllite

Giese et al., Phys. Chem. Miner. 1991, 17, 611-616

• No spreading and some hydrophobicity

- note absence of Na+ ions

• Contact angle θ = 80 ±5º in equilibrium

Experiment: θ = 79.2 ±7.4º

CLAYFF: θ = 105 ±5º X

Si Al

O H

CEC = 0

meq/100g

CHARMM-IFF

4

Metal-Organic Interfaces: Comparison of DFT (M06)

and IFF

Gupta et al. J. Phys. Chem. C 2016, 120, 17454.

CHARMM-IFF

DFT (M06-L)

5

Also lipids free energies on gold

~10% agreement with expt –Quirke et al. Chem. Phys. Lett. 2016, 664, 199;

Horsewell et al. Faraday Disc. 2002, 121, 405.

Match Between DFT and IFF Better than 10%

Gupta et al. J. Phys. Chem. C 2016, 120, 17454.

6

Peptide Binding to Silica Surfaces in Solution

at Different pH

Adsorption isotherm (experiment) Simulation (CHARMM-IFF)

0

20

40

60

80

100

50 18 9 09 7 5 3

Approx. pH

Surface ionization (%)

LDHSLHS (-)

AFILPTG (=)

KLPGWSG (+)

Tim

e in

clo

se c

onta

ctw

ith s

urfa

ce (

%)

0

2

4

6

8

10

8.5 7.4 5 3

LDHSLHS (-)

AFILPTG (=)

Adsorb

ed a

mount

(peptides p

er

nm

2 )

KLPGWSG (+)

pH

F. S. Emami, C. C. Perry, H. Heinz, et al. Chem. Mater. 2014, 26, 5725.

• Free energies of binding range from -8 kcal/mol to 0 kcal/mol in experiment and

are reproduced with ±1 kcal/mol precision in the simulationFFSiOH fails X

7

Lattice Parameters - Examples

• Computed unit cell parameters (NPT dynamics) agree ±0.5% with experimental X-Ray crystal structures (previously ±3-5%)

Example compounds cell

dim.

a

(nm)

b

(nm)

c

(nm)

α

(°)β

(°)γ

(°)V

(nm3)

rms dev

(pm/atom)

Mica

K2Si6Al6O20(OH)4

exp

sim

531 2.596

2.585

2.705

2.691

2.005

2.006

90

89.54

95.73

95.36

90

90.01

14.00

13.89

0

15

Hydroxyapatite

Ca10(PO4)6(OH)2

exp

sim

222 1.883

1.882

1.883

1.881

1.375

1.375

90.00

90.00

90.00

90.00

120.0

120.0

4.224

4.214

0

20

Gypsum

CaSO4 · 2 H2O

exp

sim

313 1.703

1.703

1.521

1.521

1.886

1.856

90.0

90.0

114.08

112.1

90.0

90.0

4.462

4.455

0

26

Tobermorite 11 Å

Ca4Si6 O15(OH)2 · 5 H2O

exp

sim

221 1.347

1.348

1.477

1.467

2.249

2.247

90

89.55

90

90.15

123.25

123.13

3.741

3.721

0

23

Gold

Au

exp

sim

555 2.039

2.039

2.039

2.039

2.039

2.039

90.0

90.0

90.0

90.0

90.0

90.0

8.478

8.477

0

1

8

Cleavage Energy and Modulus – Examples

Heinz, Emami, et al. Langmuir Feature 2013, 29, 1754.::

::

::

9

Hydration Energy as a Function of pH -

Hydroxyapatite

T. J. Lin, H. Heinz J. Phys. Chem. C 2016, 120, 4975. Chem. Soc. Rev. 2016, 45, 412.

different

mechanisms

15 10 5

Cleavage

energy

comp

expt 1000-1200 350-500

Immersion

energy in

water

reactive

600-700

Eb ~ -4.7

kcal/mol

(010)

• C-term.

• NH3+ at K7

Adsorption

of peptide

SVSVGGK

(010)

Eb ~ -9.0

kcal/mol

• S1, S3

Ca P O C N H

pH

• V2, V4

(identified by

phage display)

10

Influence of Chosen Energy Expression is Small –

Example Tricalcium Aluminate

Sometimes 5-10% lower modulus and cleavage energy using 9-6 LJ

potential (PCFF) vs 12-6 LJ potential (CHARMM etc)

Mishra, Heinz et al. Dalton Trans. 2014, 43, 10602.

11

References by Type of Compound

Below is a list of references that introduce and validate the force fields. Citing references to these papers

need also be followed for details as many groups have meanwhile used IFF and added to the validation.

• Clay minerals/layered silicates: J. Am. Chem. Soc. 2003, 125, 9500-9510. DOI: 10.1021/ja021248m. Chem. Mater. 2005, 17,

5658. DOI: 10.1021/cm0509328. J. Chem. Phys. 2006, 124, 224713. DOI: 10.1063/1.2202330. Chem. Mater. 2007, 19, 59-

68. DOI: 10.1021/cm062019s. J. Phys. Chem. C 2010, 114, 1763-1772. DOI: 10.1021/jp907012w. Chem. Mater. 2010, 22,

1595-1605. DOI: 10.1021/cm902784r. J. Phys. Chem. C 2011, 115, 22292-22300. DOI: 10.1021/jp208383f.

• Fcc metals: J. Phys. Chem. C 2008, 112, 17281-17290. DOI: 10.1021/jp801931d. J. Am. Chem. Soc. 2009, 131, 9704-9714.

DOI: 10.1021/ja900531f. Phys. Chem. Chem. Phys. 2009, 11, 1989-2001. DOI: 10.1039/B816187A. J. R. Soc. Interface

2011, 8, 220-232. DOI: 10.1098/rsif.2010.0318. Soft Matter 2011, 7, 2113-2120. DOI: 10.1039/C0SM01118E. J. Am. Chem.

Soc. 2011, 133, 12346-12349. DOI: 10.1021/ja203726n. Small 2012, 8, 1049-1059. DOI: 10.1002/smll.201102066. Nano

Lett. 2013, 13, 840-846. DOI: 10.1021/nl400022g. Many further recent papers.

• Silica: J. Am. Chem. Soc. 2012, 134, 6244-6256. DOI: 10.1021/ja211307u. Chem. Mater. 2014, 26, 2647-2658. DOI:

10.1021/cm500365c. Chem. Mater. 2014, 26, 5725-5734. DOI: 10.1021/cm5026987.

• Hydroxyapatite: Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846. J. Phys. Chem. C 2016, 120, 4975-4992. DOI:

10.1021/acs.jpcc.5b12504.

• Cement minerals/LDH: J. Phys. Chem. C 2013, 117, 10417-10432. DOI: 10.1021/jp312815g. Langmuir 2013, 29, 1754-1765.

DOI: 10.1021/la3038846. Dalton Trans. 2014, 43, 10602-10616. DOI: 10.1039/C4DT00438H.

• Calcium sulfates: Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846.

• Poly(ethylene oxide): Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846.

• Overview papers: Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846. Chem. Soc. Rev. 2016, 45, 412-448. DOI:

10.1039/C5CS00890E. For clays only: Clay Miner. 2012, 47, 205-230. DOI: 10.1180/claymin.2012.047.2.05.